The purpose of orthoses is to guide or support the movement of an existing limb or to brace and support the limb, while prostheses replace limbs that are not present. Leg orthoses are available in different embodiments, with those referred to as knee angle foot orthoses (KAFO) supporting both the foot and also the ankle joint and knee joint. The foot is generally placed on a foot plate, one or more shin rails extend parallel to the lower leg, a knee joint is provided approximately in the area of the knee axis, and fastening devices are mounted on one or more thigh rails in order to fasten the prosthesis to the upper leg. Likewise, fastening devices can be provided on the shin rails and on the foot plate so as to be able to fasten the orthosis on the respective leg.
Prosthetic devices with a prosthetic knee joint have a prosthetic foot, which is fastened to the prosthetic knee joint via a lower leg tube. Proximally from the prosthetic knee joint, a fastening device is provided for the prosthesis, which is usually designed as an upper leg socket into which the upper leg stump can be inserted. A prosthetic knee joint can have various designs ranging from a monoaxial prosthetic knee joint or a polycentric knee joint with damping means to computer-aided or driven active prosthetic knee joints. The prosthetic feet can be fastened to the lower leg tube either rigidly or in an articulated manner, while motor-driven prosthetic feet are also possible.
FR 2,549,719 A1 relates to a prosthesis with a prosthetic knee joint and with a prosthetic foot fastened to a lower leg tube in an articulated manner. A connection rod, which is coupled to the prosthetic knee joint via a lever mechanism, is arranged posterior to the ankle joint axis. When the prosthetic knee joint is flexed, the prosthetic foot is lifted and a dorsiflexion is performed.
US 2008/0269913 A1 relates to an artificial leg with a prosthetic knee joint and a prosthetic foot. On the prosthetic knee joint, a connection rod is articulated frontally with respect to the knee joint axis, such that, upon flexion of the knee, the connection rod is moved in a guide in the lower leg tube. The movement is conveyed to the prosthetic foot via a tensioning element, such that the tip of the foot is lifted in the knee flexion.
US 2009/0265018 A1 relates to a driven leg prosthesis and to a method for controlling the leg prosthesis in order to achieve an almost natural gait pattern. Both the prosthetic knee joint and also the ankle joint are provided with separate motor drives. The prosthesis is controlled in real time by sensors on the basis of different intramodal control programs.
EP 0 041 052 B1 relates to a prosthesis for a lower limb, in which an upper leg socket and a lower leg are coupled to each other via a toothed hinge. A spring-loaded piston rod lifts the toes in the event of a knee flexion.
DE 47 53 03 B1 relates to an artificial leg in which a lower leg part and an upper leg part are connected to each other by two articulated rods, in order to effect a dorsiflexion when the prosthetic knee joint is angled.
In prosthetic devices with a functional separation of knee joint and ankle joint, damping is often provided during the movement, such that the kinetic energy is converted to thermal energy. If there is a functional connection of knee joint and ankle joint, the kinetic energy is conveyed from the knee joint to the ankle joint.